BACKGROUND AND OBJECTIVE: In view of reports of fluctuations in intraocular pressure (IOP) during phacoemulsification, real-time IOP during small-incision, manual extracapsular cataract extraction (ECCE) and phacoemulsification was measured to determine the effect of anterior chamber maintainer infusion on intraoperative IOP dynamics. PATIENTS AND METHODS: A comparative study of IOP during cataract surgery was conducted by these two methods in 29 patients. An anterior chamber maintainer infused balanced salt solution continuously into the eye throughout ECCE. The anterior chamber maintainer was open in 7 cases throughout phacoemulsification and switched off during phacoemulsification in 7 cases. RESULTS: IOP measurements during small-incision ECCE were physiologic (range, 5 to 20 mm Hg) during most of the operation and coincided with the value of hydrostatic pressure established by the height of the anterior chamber maintainer infusion bottle. During phacoemulsification without concomitant anterior chamber maintainer, IOP was positive (> 2 to 3 mm Hg) as long as the phacoemulsification infusion line was activated (position 1). Moving to position 0 caused hypotony. Occlusion breaks occasionally caused wide fluctuations in IOP. Concomitant anterior chamber maintainer and phacoemulsification infusion did not prevent surges, but may account for the lower range of fluctuation. The anterior chamber maintainer also maintained a positive IOP at position 0 during phacoemulsification. CONCLUSIONS: An anterior chamber maintainer in conjunction with a self-sealing incision can maintain stable physiologic IOP during small-incision ECCE. The IOP fluctuations during phacoemulsification, especially during occlusion breaks, can be attenuated by an anterior chamber maintainer.